Internet routing architecture may be viewed as a set of domains, each domain having an internal routing environment. Each domain is a single administrative domain, operated within a uniform set of routing policies. Each domain may be operated independently from any other domain. The domain is in effect an autonomous unit in the overall routing architecture, and is termed an Autonomous System (AS). Each particular AS may appear, to other ASs, to have a single coherent internal routing plan. Each particular AS may present a consistent picture of what destinations are reachable through the particular AS. Each AS is uniquely identified using an Autonomous System Number (ASN). An ASN could be assigned, for example, to a network service provider (NSP), a large company, a university, a division of a company, or a group of companies.
The inter-domain routing environment describes how domains interconnect, but avoids the task of maintaining transit paths within each domain. In the inter-domain space, a routing path to an address is described as a sequence of domains that must be transited to reach the domain that originates that particular address prefix. Today this inter-domain space is maintained using Version 4 of the Border Gateway Protocol (BGPv4), RFC 4271.
Overlay networks are virtual network topologies implemented over physical network “substrates” (also referred to as underlay networks). Many overlay networks can execute on top of a single underlay network. An overlay network for each tenant, of a plurality of tenants, is isolated from overlay networks for other tenants.
A provider will often charge different billing amounts for different data transmissions. Data transmitted out of an AS may be billed differently based factors including the type of data transmitted, the cost to carry the data, and the quality of service associated with to the data. Billing is traditionally handled by creating traffic classification rules. The traffic classification rules are used to analyze data flow and determine the amount of transmitted data corresponding to a given traffic classification.
The approaches described in this section are approaches that could be pursued, but not necessarily approaches that have been previously conceived or pursued. Therefore, unless otherwise indicated, it should not be assumed that any of the approaches described in this section qualify as prior art merely by virtue of their inclusion in this section.